Sen. Henry M. Jackson (D-Wash.) accused the Carter administration last night of following a policy of "appeasement" toward the Soviet Union, comparing the president's policies toward Moscow to Britain's handling of Nazi Germany in the 1930s.

In a major address, the influential senator declared his unequivocal opposition not only to the new strategic arms limitation treaty (SALT II) as negotiated but also to the course of U.S. Soviet relations as conducted by Carter and the Nixon and Ford Administrations. It was Jackson's strongest public statement on the issue and came just before this weekend's U.S. Soviet summit.

"In the seven years since the Moscow summit of 1972," Jackson said, "we have been testing the proposition that despite the lessons of history, it is possible to achieve an accommodation with a totalitarian superpower through negotiated agreement . . . The danger is real that seven years of detente are becoming a decade of appeasement."

In a speech of the Coalition for a Democratic Majority, a conservative Democratic group, Jackson criticized SALT II, U.S. trade policy toward the Soviet Union and the idea that the recent increase in Jewish emigration from the Soviet Union would "justify" waiving the Jackson-Vanik amendment and granting both tariff benefits and credits to Mowcow.

My friends, we have been making too many gratuitous concessions, we have silenced too many officials, bent too many laws and traditions and apologized too often.

"In the area of trade and technology, the right of emigrate and strategic arms, the signs of appeasement are all too evident," Jackson said.

He aimed some of his harshest words at the SALT II accord, which Carter and Soviet President Leonid Brezhnev are to sign next Monday in Vienna."To enter a treaty which favors the Soviets, as this one does, on the ground that we wil be in a worse position without it, is appeasement in its purest form," Jackson said.

". . . Against overwhelming evidence of a continuing Soviet strategic and conventional military buildup, there has been a flow of official administration explanations, extenuations, excuses," Jackson said.

"It is all ominously reminiscent of Great Britain in the 1930s when one government pronouncement after another was issued to assure the British public that Hitler's Germany would never achieve military equality - let alone superiority.

"The failure to face reality today - like the failure to do so then - that is the mark of appeasement."

Jackson's harshly worded speech, coming just as Carter was preparing to leave for his summit with Brezhnev, clearly displeased Carter administration officials. One administration called it "an escalation of rhetoric," when asked, and suggested that Jackson decided on his hard-line speech because the administration was receiving a "position response" to its campaign to win public support for SALT.

Another White House official commented: "It's regrettable that Sen. Jackson would make these comments on the eve of the summit meeting in Vienna and before he has completely reviewed the terms of the SALT treaty. His accusations concerned 'appeasement' are ill conceived, ill timed and ill informed."

Traditionally, Jackson has played an influential role in the Senate on national security policy as a hardliner whose expertise and experience commanded the respect of many colleagues. Recently, however, a number of senators have begun to speculate privately that Jackson's increasingly strident positions may be isolating him from the moderate mainstream of the Senate where he has been most effective in the past.

Jackson and his talented staff appear confident that the senator can continue to be a decisive influence, particularly in the coming debate on SALT II.

One of Jackson's aides said yesterday the senator hoped his speech would be "taken to heart - and taken to Moscow" by the Carter administration.

Jackson began his speech with his description of recent events:

"In the last seven years, we and the Soviet Union have gone jointly into space. The Soviet Union has gone alone into Ethiopia.

"We have sent our scientists to Moscow. The Soviets have sent their Cubans to Angola.

"We have encouraged peace in the Middle East. The Soviets have encouraged war in Southeast Asia.

"We tried to calm the turmoil in Iran. The Soviets sought to aggravate it.

"We have encouraged human rights around the world. The Soviets have trampled human rights at home.

"We have exercised restraint in the acquisition of strategic weapons. The Soviets have invested, in the last decade, over $104 billion more than the United States in strategic nuclear forces alone."

Jackson charged that the United States is becoming strategically inferior to the Soviets, allowing them to outspend America in all military categories and outstrip America in all significant strategic categories but one, total nuclear warheads. By 1985, Jackson said, "the Soviets will have achieved superiority in the number of warheads as well."

"And all this is taking place in a misty atmosphere of amiability and good fellowship under a policy of detente," Jackson said. "This is appeasement."

Jackson said the United States should continue to deny most-favored nation tariff status and trade credits to the Soviets until they free political prisoners and all Jews who want to emigrate. Jackson implicitly discounted the recent, sharp increase in Soviet Jewish emigration to a rate of nearly 5,000 a month. The Jackson-Vanik amendment requiring freer emigration as the price of trade benefits has not been satisfied, Jackson said. "Bending the meaning of the law" to please the Soviets "is appeasement." he charged.

In summary, Jackson said: "The fateful question for us is whether the United State can conduct an effective foreign policy - one which will assure our national security and the safety of other free nations - from a position of strategic inferiority."